Simulating low-velocity impact induced delamination in composites by a quasi-static load model with surface-based cohesive contact

In this paper, a computationally efficient finite element model is presented for predicting low-velocity impact damage in laminated composites using a quasi-static load model with surface-based cohesive contact. The effect of compressive through-thickness stress on delamination is taken into account by introducing contact friction force in the shear force direction. Damage onset and propagation in a cross-ply plate [903/03]S is simulated and the numerical results agree well with the experimental observation in terms of damage location, shape and size. Through-thickness stress analysis shows that resistance to the upper interface delamination propagation is mainly contributed by the friction force due to the high compressive through-thickness stress, whereas, for the lower interface, it is the cohesive behaviour that controls the delamination initiation and propagation. Predicted delamination area is not sensitive to the interlaminar friction coefficient when it is greater than 0.6. The range of friction coefficient of the interlaminar contact is recommended to be between 0.6 and 0.9.